Drumming noise from front drivers wheel

A low drumming noise that changes with speed has just started on my 200 Venture. I have 156,000 miles on the clock, is well looked after and has been a dream car for me. I am suspecting it is a wheel bearing. I understand they are a sealed unit, just want to know if I am on the roght track before I buy a new one. Also is it wise to change out both sides at the same time.
 
Appreciate the help.
 
Thanks.
 
Ian.

Sounds like the bearings to me.  I replaced both front wheel hub/bearings on my '03 at 15000 miles.